1. Field of the Invention
The present invention relates to a vehicle lamp fixture that includes a so-called wraparound lens and more particularly to a structure for mounting such a lens to a lamp body.
2. Prior Art
FIG. 4(a) shows a generally known prior art structure for mounting a lens to a lamp body.
In this vehicle lamp fixture, an attaching leg portion 2a formed at a location near the outer edge of a lens 2 is inserted into an attaching grooved portion 4b formed in a front end open outer edge portion 4a of a lamp body 4, so that the attaching leg portion 2a and the attaching grooved portion 4b are brought into a hook-engagement. This hook-engagement is obtained by engaging a hook 2b formed on the outside wall surface of an attaching leg portion 2a with a hook engaging hole 4c formed in the attaching grooved portion 4b.
However, this prior art structure causes problems when the hook-engaging structure is employed in a vehicle lamp fixture in which an end portion of the lens is curved so as to wrap around the rear side thereof as shown in FIG. 4(b).
More specifically, in this type of lens, a rear wall surface 2c1 of a lens outer edge portion 2c, which is located further toward the outside of the attaching leg portion 2a, is formed parallel to or so as to expand toward the outside with respect to the distance between the rear wall surface 2c1 and the front end surface 2b1 of the hook 2b. This is due to the structure of a die for forming the lens so that any undercut can be prevented from occurring, making it possible to use a slide die. In order to accomplish a reliable hook-engagement, it is also necessary to form the front end surface 2b 1 of the hook 2b so as to engage with the front end surface of the hook engaging hole 4c at an angle equal to or greater than a right angle.
As a result, a secure hook engaging function is demanded, the lens outer edge portion 2c needs to have a trapezoidal cross-sectional shape as shown by the solid line in FIG. 4(b) with the base end portion thereof made large in thickness. However, this causes a surface sinking problem, that reduces the quality of appearance of the lamp fixture.
On the other hand, when the lens outer edge portion 2c is designed to have substantially a constant thickness so as to prevent the surface sinking in the lens 2 as shown by the chain double-dashed line in FIG. 4(b), then another problem occurs. The front end surface 2b1 of the hook 2b abuts diagonally on the front wall surface of the hook engaging hole 4c; and the hook 2b tends to be easily separated from the hook engaging hole 4c. Thus, a sufficient hook-engagement is hindered.